1. Field of the Invention
The present invention relates to a shovel including a hydraulic motor for boom regeneration and a method of controlling a shovel.
2. Description of the Related Art
A hybrid type shovel is known that includes a motor generator rotatively driven by a hydraulic motor for regeneration when a boom is lowered or an arm is closed.
The hybrid type shovel rotates the hydraulic motor for regeneration by using hydraulic oil flowing out of a bottom side oil chamber of a boom cylinder when the boom is lowered, or hydraulic oil flowing out of a rod side oil chamber of an arm cylinder when the arm is closed. As a result, the hybrid type shovel recovers positional energy of the boom or the arm as electrical energy by working the motor generator coupled with the hydraulic motor for regeneration as a generator.